Spamassassin stopped working!

Over the last few days spamassassin started registering Hits: 0 just out of the blue. Every once in a while an email will get scored, but most are not. It had been working fine for months. This has caused all of the email accounts on this server to receive 100s of spams a day! No changes were made. What happened? Any ideas?

Looks like we got it figured out. But if anyone else has this issue - here is what we did . . .
the sa-updates.openprotect.com rule-set looks like is what was causing all hits to be 0 (Hits: 0) on all incoming emails. We ran sa-update -D to download the default rule-set and restarted spamassassin and it is now scoring emails properly. We are going to discontinue running the sa-update on the openprotect.com rule-set for now.